Real-Time Collaboration, Undo Support, and Improved Transcription Sync

✨ New Features

• Added undo/redo functionality in both personal and collaboration modes
  Undo/redo demo
• Enabled real-time collaboration: synchronizing branch selection, content, and structure rearrangement
  Branch selection sync example
  Branch content sync example
  Structure sync demo
• Added transcription word and user input sync across tabs
  Word sync example
  User input sync demo
• Introduced single-instance control: only one browser tab can record or generate a mind map from transcription
  Feature example
• Implemented audio sync across browser tabs
  Audio sync demo
• Redesigned pricing page with monthly/yearly switcher and contextual buttons
  Pricing page preview

🔄 Improvements

• Unified "Fit to map" and "Justifier" tools with consistent zoom behavior
  Zoom behavior example 1
  Zoom behavior example 2
• Increased branch text width for better readability
  Before → After
• Slightly moved branch resizer to avoid placing caret after resizing
  Caret fix screenshot
• Changed hotkey and menu behavior to prevent glitches when holding Enter
  Enter key bug fix example
• Improved handling of branch positioning with Shift + Tab
  Before → After

🛠 Fixes

• Fixed invisible part of caret
  Caret fix screenshot
• Fixed bug where selection disappeared in collaboration selector
  Selector bug example
• Fixed color sync glitch during collaboration
  Before → After
• Fixed issue with saving after transcription word edit
• Fixed crash during sync when branches were present but paragraphs were not
• Fixed default center node not appearing in new mind map
• Prevented extra save trigger when opening second mind map tab
• Prevented data loss when creating branches in another tab
• Allowed saving local mind maps on desktop app even without internet

And other improvements